160 
Table 1. 
Ped. No. 
06196 
06197 
06212 
Bursa hp. simplex {abC) X Bursa H. heteris (ÄBc) 
Ped. No. 056.64 
Ped. No. 059. 
Bursa hp. heteris (ABC) 
Ped. No. 0564.88 
Ped. No. 059.89 
Bursa-pastoris Series (C) 
Heegeri Series (c) 
Total 
Expected 
I i I I 
heteris rhomboidea tenuis simplex 
98 32 36 13 
1032 302 331 78 
317 67 102 21 
1447 
1368 
401 
456 
469 : 112 
456 : 152 
heteris rhomboidea tenuis simplex 
5 2 11 
45 13 13 1 
19 4 7 0 
69 
63 
19 
21 
21 
21 
C: c 
19.9 : 1 
24.2 : 1 
16.9 : 1 
21.9 : 1 
3.0:1 
The deficiencies seen to be consistently present in all these 
pedigrees in the number of rhomboidea and simplex were pro- 
bably due at least in part to an error of Classification, those rhom- 
hoideas having the greatest elongation of the terminal segment 
of the lobes having doubtless permitted their Classification a& 
minus-fluctuations of heteris^ and the sharpest-lobed simplex as- 
minus-fluctuations of tenuis. The greatest surprise was occasioned 
by a ratio of about 22 : 1 in the form of the capsules, as it was- 
thought probable that the difference between the two form» 
would be found to be dependent upon the presence and absence 
of a Single gene, the expected ratio on this assumption being 3 : 1. 
At the close of the second generation the cultures were 
necessarily discontinued, and could not be resumed until in the 
autumn of 1910. The appearance of a paper by Nilsson-Ehle ^)y. 
showing that certain characters of wheat and oats are independ-^ 
ently determined by two or more distinct units or genes, gave 
the Suggestion that the capsule-character of B. bursa-pastoris 
might be determined in like manner by two genes, the absence 
of both of which produces the Heegeri-tyi^e of capsule, although the 
observed ratio 22 : 1 is a bad approximation to the expected ratio 
1) Nilsson-Ehle, H., Kreuzungsuntersuchungen an Hafer und Weizen, 
pp. 122. 1909. Lund: Hakan Ohlssons Buchdruckerei. 
